Decarbonisation Technology May 2022 Issue

Carbon capture application to ethylene plants Operationally proven carbon capture applied to ethylene plants, with examples of deployment in new and existing plants

Myrian Schenk and Jim Middleton Technip Energies

T he production of ethylene originates mainly from steam cracking. This thermal process uses a large amount of energy and, as such, is a significant emitter of CO2 in the industrial sector (Middleton, 2021). The reduction of CO₂ emissions from the cracker can be achieved by replacing the methane fuel from the process with alternative lower carbon fuels, such as hydrogen, or installing electrical heating. However, a third option to reduce CO₂ emissions is to add a post- combustion carbon capture plant. Post-combustion carbon capture (CC) has been proven in the power industry and can be applied to steam crackers. Apart from the use of high hydrogen content fuels, CC is the only currently commercially proven technology that can achieve very high levels of reduction of CO₂ emissions from steam crackers (Middleton, 2021). In this article, we will highlight some studies carried out by Technip Energies, in which we show the feasibility of installing a CC plant on a steam cracker and that the operation of the steam cracker should not be affected by the addition of a CC plant. The installation of CC, both on a new cracker design or as a retrofit to an existing cracker, is relatively straightforward, provided the designer of the CC plant understands how the cracker operates to allow for smooth integration. The right decisions must be made for the proper functioning of the two plants together. The main requirements are: • A destination for the captured CO₂ • A plot area, if possible close to the furnaces (and auxiliary boilers if the capture is planned for these units too) • The utilities required to run the CC plant

The modifications to ethylene plants to accommodate the addition of a CC plant are principally in the flue gas and utility areas. Therefore, it is relatively straightforward to design new ethylene plants to allow for the future installation of a CC plant; indeed, Technip Energies is currently designing two such plants. The use of CC on ethylene plants can be complementary to other methods of CO₂ reduction, such as partial hydrogen firing and reduced conventional firing in furnaces, both of which reduce flue gas flow rates and lower the operating and capital costs of the CC plant. The 'conventional' routes for captured CO₂ are for enhanced oil recovery (EOR) or sequestration; however, more and more alternative uses of captured CO₂ are starting to emerge. Post-combustion carbon capture technology Continuous improvement in the affordability of CC is key to enabling the technology to play its part in worldwide CO₂ reduction. The integration between CC technology and CC and cracker engineering represents a significant step towards achieving this goal. At Technip Energies, we maximise the benefits of our alliance with Shell Catalysts & Technologies, licensor of the Cansolv CO₂ capture technology, to provide a single point delivery of projects. Since 2012, we have had an exclusive alliance with Shell Catalysts & Technologies for the power industry. However, in recent years, we have extended our cooperation across numerous projects and sectors in the carbon capture, utilisation and storage industry. Together, we work on technology and engineering improvements and drive integration